Electrical control system



Aug. 3 1926.

J. A. LUNN ELECTRICAL CONTROL SYSTEM Filed Oct. 16, 1924 BY 1 v HIS ATTORNEYS Patented Aug. 3, 1926.

UNITED STATES PATENT OFFICE.

J'OHN A. LUNN, 013 BOSTON, MASSACHUSETTS, ASSIGNOR, BY MESNE ASSIGNMENTS,

TO NATIONAL BEFRIGERATING COMPANY, OF BOSTON, MASSACHUSETTS, A COR- PORATION OF MASSACHUSETTS.

ELECTRICAL CONTROL SYSTEM.

The present invention relates to refrigerating machinery and to methods of operation thereof. It relates particularly to such apparatus in which refrigeration is obtained through quicklycooling over a wide range of temperature the atmosphere in a chamber connected to a refrigeration chamber containing a refrigerant such as ammonia. It further relates to electric switching apparatus for automatically controlling various steps in the cycle of operations of the apparatus of my invention.

The essential refrigerating apparatus of my invention, including refrigeration chamber, generator, condenser, etc., are described in detail in the companion application of Frederick G. Keyes, Ser. No. 359,882, to which reference is hereby made. I have illustrated the apparatus of the present invention in the accompanying drawing in which is shown schematically an arrangement of the electrical apparatus, switches, and controlling means applied to the apparatus 0f the application of Frederick G. Keyes,.Serial Number 673,105.

Referring to the drawings, a distillation chamber or generator 13 has mounted therein an electric heating coil 15 which is connected through the wires 1 and 2 to electric supply mains 11 and 12 respectively. Between wire 2 and main 12 there is connected one side of a three-electrode mercury switch 160, wire 2 being connected to side 160 and main 12 being connected through wire 8 to the mid-point 160 of the switch. A parallel circuit consisting of wire 7 connects to side 160 of the switch 160 one side of solenoid 170 which moves the operating armature of water valve 171 which is described in J ohnson application No. 735,551. The other side of solenoid 170 is connected through wires 172, terminal 181 of side 181 of time switch 180, through mercury 180 when present, ad-

jacent terminal 181", wire 194, to main 11, another parallel circuit from terminal 181", wire 173, solenoid 52 which operates armature 54, by conductor 63, to contact 64 which is at the lower limit of movement of contactor 58, contact 64 with contact 65 acting as stops for said contactor 58 at said lower limit of movement and also'acting as circuit making means therewith through wire 66, wire 61, to line 12, as described in cop'end- 7 ence is ing applicationof Frederick G. Keyes, Ser.

No. 673,105, and as hereinafter further described. The mercury time switch 180 is described, in Hesse application filed concur-V wire 61 to main 12.

' From these connections it can be seen that solenoids 53 and 191 are simultaneously energized and also that solenoids 52 and 170 are simultaneously energized at the difi'erent positions of said switch 160. Said time switch 180 serves, by the timed flow of mercury 180 therein "as described in said Hesse application cited above to which refer ereby made, to deenergize said solenoids 170 and 191 at the expirationof a given period of time aftertheir respective ener'gizations..

Mechanically connected to switch 160 is the mercury switch 180 which comprises a tubular envelope divided into two chambers 181 and 182 connected by a capillary 183 and having mercurysealed therein and two electrode terminalssealed therethrou'gh at each of said chambers 181 and 182; 181 and'181 at one end and 182* and 182 at the other end. 'Apressure equalizing tube 184 connects chambers 181 and 182 between their tops. This switch 180 is mounted in the same plane as switch 160and-so connected to it that when the latter is tipped to close the 160 side the mercury in switch 180 will flow to cause mercury to flow to the end in which are teminals 181 and 181 and complet'e electrical connection therebetween. It Is also arranged so that when switch l60-is tipped to close the160 side the mercury in switch 180 vwill be caused to flow to the end in which are electrodes 182 and 182". Now as the mercury in time switch 180 takes an appreciable amount of time toflow from one sideto the'other (say 5 seconds), it can be seen when the switches 160 and 180 are first moved into the position shown in Fig.1 of the drawing that side 181 of switch 180 is closed during part of the time (first 5 seconds) that the circuit between 181 and 181 is closed. Likewise when tipped in the other direction side 182 is closed .during the first 5 seconds that 182, 182 are connected.

When switch 180 is first brought to the position shown in Fig. 1 and before the mercury therein leaves chamber 181, connection is made from main 11, 'wire 194, mercury 180 in chamber 181, wire 172, solenoid 170, wire 7, electrode 160*, 160, wire 8, to main 12. A parallel circuit goes from 181, wire 173, through solenoid 52, wire 63, contact 64, contactor 58 (when at its lower limit), contact 65, connector 66, wire 61, to main 12. Solenoid 170 is shunted with solenoid 52 through side 181 of switch 180. It can also be seen that solenoids 191- and 53 are energized and deenergized simultaneously. In the manner of the switching arrangement shown and described in copending application of Frederick G. Keyes,

Serial No. 359,882, filed February 19, 1920, to which reference is hereby made, time switch 180 is mounted on a pivoted bar (not shown) which is mechanically connected to armatures 54 and 55 through which it is controlled by solenoids 52 and 53 respectively.

Distillation chamber 13 is connected to the condenser which is composed of condensing coil 21 and condensing chamber 16 by way of pipe 17, manifold 18, through check valve 19, to pipe'20, coil 21, pipe 22, to chamber 16. The check valve allows the refrigerant .to flow through it from generator 13 tothe condenser 16, 21 but prevents flow through it in the opposite direction. From the condenser, passage is provided for the liquid refrigerant through pipe 24 to the refrigerating chamber 25 and coils26. From chamber- 25 connection is made through pipe 27, check valve 28, manifold 18, and pipe 17 to the interior of generator 13. The check valve 28 allows the refrigerant to flow through it from the refrigerating chamber 25 to the generator 13 but prevents How in the opposite direction.

In connection with the generator 13 and the condenser 16, 21 is a cooling system of water supply and distribution pipes, cooling coils, and an electrically controlled two-way valve 171 which latter serves to direct the fiow of the-water alternately through the cooling coils of said generator 13 and con denser 16, 21. The pipe 30 connects the cooling system to the water supply mains through said two way valve 171. The pipe '31'connects the main 30 through the ports at one position of the valve 171 to the coolng coils 36 of thev generator 13. Discharge 1s madefrom coils 36 to discharge pipe 35. The main 30 is also connected through the valve 171 at its other position through pipe 32, cooling coil 33, pipe 34, to discharge pipe 35. Coil 33 surroundst-he condensing chamber 16 and coiled within it is the condensing coil 21, 22.

The valve 171 is operated to direct the water flow either through pipe 31 or pipe 32 by means of solenoids 191 and 170, respectively, which are through the automatic electric switching means alternately energized at the proper steps in the cycle of operation of the refrigerating machinery as hereinafter fully described.

In connection with time switch 180 there operates the float controlled contactor 58 in refrigeration.chamber 25 and which is carried by float 62,. At the minimum of refrigerant liquid level in chamber 25 contacior 58 closes the circuit through contacts 64 and 65. As the liquid level rises in said chamber 25 the contactor 58 rises with float 62 and is stopped at a critical level by contacts 57 and 58 through which at this level it closes a circuit.

Starting with the apparatus in the position shown in the drawing and with refrigerant fluid in the generator 13 and contactor 58 at its lowermost position the operation of my device is as follows: The 182 side of time switch 180 being closed, current will pass through the heating coil 15 coming from main 11 through conductor 1, heating coil 15, conductor 2, side 160, mercury 161, and mid-point 160 of switch 160, conductor 8, to main 12. At this time valve 171 is open to deliver cooling water through pipe 32 to cooling coil 33 about condenser coils 21.

Upon the generation of heat in coil 15 the refrigerant in chamber 13 is driven out of the absorbent and by the resulting pressure is forced out through pipe 17, through manifold 18 and check Valve 19 to coils 21, 22 and condenser chamber 16 where it is condensed. Upon the accumulation of suiticient liquid in said chamber 16 to raise the float and open the valve 73 therein as described in companion application Serial No. 673,105, the liquid refrigerant flows out through said valve 73 into the refrigerator chamber 25. Successive accumu ations of liquid flow from chamber 16 to chamber 25 and as the liquid level rises in the latter fioat 62. is raised until contactor comes in contact with contacts 57 and 59, whereupon a new electric circuit is established. In this newly made circuit current flows from main 12 through conductor 61, contact 59, contactor 58, contact 57, conductor 56, solenoid 53, conductor 193, terminal 182*, mercury 180 terminal 182, wire 194, to main 11, at which time the time switch is tipped so that the mercury 180" flows from side 182 to side 181, said circuit between 182 and 182 will be continued yet for about five seconds until the flow -b'fjm ercury from between them is completed." Simultaneously there is comwater through pipe 32 to cooling coil 33 and to allow water to flow through pipe 31 to the cooling coil 36 of the generator 13, the current being cut off by the flow of mercury from one side of switch 180 to the other after the moving of said valve has been insured.

The heating coil 15 is deenergized by the flow of mercury 161 from between contacts 160 and 160 of switch 160.

The water flowing through coils 36 cools the generator' chamber 13 quickly and through a wide range of temperature with the result that the pressure therein is greatly reduced and in consequence thereof the liquid refrigerant in refrigerating chamber 25 rapidly evaporates and expands, flowing through pipe 27, check valve 28, manifold 18, and pipe 17 into the generator 13. The heat absorbed by the refrigerant during its evaporation and expansion reults in the reduction of temperature desired in the refrigerator chamber 25 and expansion coils 26.

As the liquid in chamber 25 evaporates the float 62 falls until contactor 58 contacts with contacts 64 and 65, thereby closing circuit from main 12 to conductor 61, conductor 66, contact 65, contactor 58, contact.

64, conductor 63, solenoid 52, conductor 173, terminal 181, mercury 180 then in side 181,

terminal 181*, wire 194, to line 11, upon the energization of solenoid 52 at this time with 160 and 180 tipped to the position shown in the drawing. Upon such movement a'parallel circuit is established for five seconds from main 12 through conductor 8, terminal 160 of switch 160, mercury 161, terminal 160, conductor 7, solenoid 170, conductor 172, side 181 of switch 180, conductor 194, to main 11. Upon the establishing of this circuit solenoid 170 is energized whereupon water valve 171 is actuated to close the water supply to coils 36 and to open it to coils 33, said solenoid 170 remaining energized until the mercury in switch 180 flows .from side 181 to side 18 2.

The flowing of the mercury from side 160 A Of switch 160 to side'160 closes the heating coil circuit from main 11, conductor 1, heating coil 15, conductor 2, side 160 of switch 160, conductor 8, to main 12 when the cycle of operations of the apparatus is completed and begins anew to continue in successive cycles while mains 11 and 12 are energized. What I claim is In-a refrigerating apparatus, in combination, a generator having a condensing chamber therefor with a one-way conduit therebetween, a refrigerating chamber connected to said condensing chamber and connected to said generator througha one-way conduit, 8. source of electric current, an electric heater for said generator, pipe coils., for said condensing chamber, pipe coils for said generator, a source of water supply connected through a two-way valve in one position to said condensing chamber coils and in the other a position to said generator coils, an armature connected to said valve for the actuation thereof, an electro-magnet in operative relation with said armature to open the valve to the generator coil and close it to the condensing chamber coil, an electro-magnet for opening .the valve to the condensing chamber coil and close it to the generator coil, a mercury switch having two co-operats ing electrodes in each end and means therein for delaying the mercury flow from one end of the switch to the other when it is tilted to one side or the other, pivotally mounted in fixed relation with a mercury switch having an electrode at each end, a common electrode therebetween and a" connection from said common electrode to one of the mains of said electric supply source and a connection from one of the end electrodes through said electric heater to the other supply main, 8.

connection from the other end electrode through one of said valve electro-magnets' and through the terminals of one end of the first said switch (which when the mercury signature.

JOHN A. LU'NN. 

